Ethernet is rapidly becoming the protocol of choice for consumer, enterprise and carrier networks. It is expected that most networks will evolve such that Ethernet will be the technology used to transport all the multimedia applications including, for example, triple-play, fixed-mobile-convergence (FMC), and IP multimedia sub-systems (IMS). Existing network elements which offer network access using Ethernet technology are not designed to make maximum use of the legacy network links existing at the edge of the carrier networks. The edge of the network is quickly becoming a bottleneck as the new applications are becoming more and more demanding for bandwidth.
Telecommunications carriers are constantly looking for new revenue sources. They need to be able to deploy rapidly a wide ranging variety of services and applications without the need to constantly modify the network infrastructure. Ethernet is a promising technology that is able to support a variety of application requiring different quality of service (QoS) from the network. The technology is now being standardized to offer different types of services which have different combinations of quality objectives, such as loss, delay and bandwidth. Bandwidth objectives are defined in terms of committed information rate (CIR) or excess information rate (EIR). The CIR guarantees bandwidth to a connection, while the EIR allows operation at higher bandwidth when available.
RF Switch
In order to increase their revenue potential, the carriers need a cost effective way to reach new customers which cannot currently serviced because there is no practical way of providing them with a broadband physical connection. New high bandwidth wireless technology, such as WiMAX or high speed RF technology allows the carrier to reach a new customer or a customer that is not currently serviced with high bandwidth without the high cost of deploying new fiber routes. The following description uses Wimax as an example, but any point-to-point RF technology could be used. By deploying WiMAX at the access of the network, the carriers can rapidly open up new markets. However, currently the Ethernet access solutions using WiMAX technology are costly, from both operating cost (OPEX) and capital cost (CAPEX) standpoints, as each access point requires a combination of a WiMAX base-station 10 with a router 11 (FIG. 1). Although WiMAX operates at higher speed, it is still important to maximize the use of its bandwidth since spectrum is a limited resource. But because the (WiMAX radio 105 and the router 102) are separate, the router has no knowledge of the radio status, it is difficult to make maximum use of the wireless bandwidth. WiMAX currently allows for multiple users to share a base station. If a subscriber does not reach the base station directly, it can tunnel through another subscriber which has connectivity. This architecture allows multiple subscribers to reach a base station which is connected to the wired network. One major issue with this architecture is that the bandwidth consumed by the tunneled subscriber is not managed and can affect the bandwidth and QoS of the service of the subscriber which is sharing the connectivity to the base station. Such architecture, which limits the subscribers to being not farther than two hops from the base station, is targeted for residential customers with less stringent QoS requirements. It is not well suited for designing enterprise networks or carrier infrastructure.
Anticipating Radio Link Performance Changes
Compared to optical transmission, wireless links are regularly subjected to impairments due to weather or other interferences. These impairments temporarily affect the bandwidth transmitted on the link. Since the base station 105 (FIG. 1) is temporarily decoupled from the switching network, there is no mechanism for the network elements to take into account link degradation and to manage the flow of data on the network. This will typically result in a large amount of packets being dropped at the WiMAX radio 105 as the Switch/Router 102 only knows if the Ethernet connector 103 is up or down and will send more packets than the radio can handle.